On production of a mold for pressing, for example, with a casting as a material, machining such as cutting work and the like for long hours is conventionally required to finish a cast material that is to become a mold.
Specifically, after a member for a mold is cast, the mold member is machined and finished to be a mold, and on casting of the mold member, a large allowance or excess of mold material is present at the margin of the mold member that will require additional work by machining. This is because the cast mold model that is a basis of the mold member is manually produced in many cases, as well as that the precision of casting itself is low. Specifically, if the amounts of precision of a model and casting deformation are estimated, the margin requiring extra work becomes large from the viewpoint of compensating for the shrinkage that occurs during casting, thus making it necessary to prevent the cutting margin from running short.
As a waste portion of the cast mold model increases, the margin of the mold requiring extra work tends to be larger than necessary.
On the other hand, the mold industry is required to satisfy the demands for complicatedly shaped products formed from molds, while reducing the cost and lead time to produce the molds.
Accordingly, a reduction in the margin of the mold requiring work can be considered to reduce the machining time for a mold member, but even if a numerically controlled working machine or the like is used for production instead of manually making a cast mold model, a mold with high precision cannot be expected when a casting is used as the mold member, and as a result, the mold margin requiring work cannot be sufficiently reduced, which makes it impossible to reduce the machining time.
In view of the above-described fact, an object of the present invention is to provide a method and an apparatus for producing a mold capable of reducing a machining time after the casting of a mold member.